Display device
The object of the present invention is to make it possible to form an LIPS TFT and an oxide semiconductor TFT on the same substrate. A display device includes a substrate having a display region in which pixels are formed. The pixel includes a first TFT using an oxide semiconductor 109 . An oxide film 110 as an insulating material is formed on the oxide semiconductor 109 . A gate electrode 111 is formed on the oxide film 110 . A first electrode 115 is connected to a drain of the first TFT via a first through hole formed in the oxide film 110 . A second electrode 116 is connected to a source of the first TFT via a second through hole formed in the oxide film 110.
1. A display device comprising;
a substrate having a display region in which pixels are formed,
each of the pixels includes a first TFT having an oxide semiconductor,
a first insulating film is formed on the oxide semiconductor,
a first gate electrode of the first TFT is formed on the first insulating film,
a first electrode is connected to a drain of the first TFT via a first through hole formed in the first insulating film,
a second electrode is connected to a source of the first TFT via a second through hole formed in the first insulating film,
a drive circuit formed on the substrate includes a second TFT having LTPS,
a second insulating film formed between the first TFT and the substrate, and
a second gate electrode of the second TFT is formed on the second insulating film,
wherein the LTPS is formed between the second insulating film and the substrate, and
wherein a metal film for the first TFT is formed on a same layer and is formed with same material as the second gate electrode of the second TFT.
2. The display device according to claim 1 , wherein the display region further includes another TFT having LTPS.
3. The display device according to claim 1 , wherein the drive circuit further includes another TFT having the oxide semiconductor.
4. The display device according to claim 1 , wherein the first through hole and the second through hole are formed in the first insulating film as seen in a plan view.
5. The display device according to claim 1 , wherein a wall of the through hole formed in the first insulating film has a first taperθ 1 on a side opposite to the oxide semiconductor and a second taperθ 2 <θ 1 on the oxide semiconductor's side.
6. The display device according to claim 1 , wherein the first insulating film is AlOx.
7. The display device according to claim 6 , wherein a refractive index of the AlOx is in a range from 1.58 to 1.65.
8. The display device according to claim 1 , wherein the first insulating film is formed of multiple layers of AlOx.
9. The display device according to claim 1 , wherein the oxide semiconductor is IGZO, ITZO, IGO, or a combination of some of these materials.
10. The display device according to claim 1 , wherein a third insulating film is formed between the first gate electrode of the first TFT and the first insulating film.
11. The display device according to claim 1 , wherein the display device is a liquid crystal display device.
12. The display device according to claim 1 , wherein the display device is an organic EL display device.